Walk Softly - Frogs and Toads - The Rest of the Story

by Geoffrey Carpentier

Continuing with our discussion about the frogs and toads of North Durham and the Kawarthas, let’s start with the one which doesn’t look like the others, the American Toad.

One of only two species of toads found in Ontario (the other is the rare Fowler’s Toad), this large, brown creature is shunned by many people because they think it can give them warts; not true. Toads are covered in spots of varying sizes and shapes and come in hues of brown, reddish or olive, but the two large ‘warts’ on the back of the head contain glands which can secrete a toxin to ward off predators.

Breeding takes place in permanent or temporary standing water, where each male courts the females with a unique long-lasting trill. Once she finds his amorous intentions acceptable, they mate and she lays her strings of eggs, consisting of between 2000 and 15,000 eggs. The small black tadpoles hatch out, after two to seven days, and these tiny aquatic creatures feed in the water for the next six to nine weeks. After which, they emerge, become terrestrial and wander forests and fields looking for food, such as insects, worms and slugs. These baby toads are amongst the smallest of all amphibians, when they head out to forage on land. Winter is spent on land in burrows below the frost line, and they emerge early in spring, as soon as the frost is out.

The American Bullfrog is our largest frog, and its booming (sounding like ‘baroom’) voice used to be a common night-time sound heard from our wetlands. Although not uncommon locally, its status has become increasingly precarious, in the past few years, and warrants careful scrutiny and perhaps protection across parts of its range. Its decline has been triggered in part by humans over-hunting it for food and by harvesting it for lab specimens for school dissection exercises. These big green coloured frogs which are up to 16 cm long, have large eardrums (tympani), partially framed by an obvious fold of skin. In the similar Green Frog, these folds run along the sides of the back, rather than around the tympani. Male Bullfrogs have bright yellow chins and can be quite similar to the Green Frog. Preferring large permanent bodies of water, Bullfrogs breed from mid-June to late July, laying up to 20,000 eggs at a time. These eggs are free-floating, for a while, and eventually hatch, then the free-swimming tadpoles feed on plant and animal material for the next one to three years. The adults are superior hunters and eat everything from birds to reptiles to large insects and even small mammals. Winter is spent in deep ponds, rivers and lakes.

The Green Frog produces a diagnostic ‘gump’ call, from permanent water bodies. Winter is spent underwater in the mud. Breeding takes place in late spring, when 1000-5000 eggs are laid, and after hatching, the tadpoles take one to two years to mature as they feed on invertebrate prey. They freely travel significant distances between water bodies in search of food and suitable aquatic habitats.

Sadly, gone from most of Durham Region now, the Western Chorus Frog is a tiny, 3 cm, gray-green to brown treefrog, of open forests which have shallow, woodland ponds. Able to be completely frozen, they overwinter underneath logs or underground. Short-lived, normally two to three years, these are early emerging frogs which lay 150-800 eggs, and are attached to submerged vegetation. The eggs hatch in a few weeks and tadpoles morph into adults about two months later.

The Gray Treefrog is a unique frog which can change colours, based on its surrounding environment (i.e. green, gray or brown). They are superb climbers, as they use the suction cups on their feet to grip surfaces. Seldom seen outside the breeding season, they are quite vocal, as they hide in holes, under tree bark or in leaf litter, where they overwinter. Eggs are laid in early spring, in shallow ponds and water-filled depressions, numbering, 1000-2600. Young emerge in about two weeks and then turn into adults at about two months old.

So now you’ve met all our amphibians and hopefully have a better understanding of them, as they quietly go about their business. Now is the time to enjoy these wonderful creatures.

Geoff Carpentier is a published author, expedition guide and environmental consultant. Visit Geoff on-line on LinkedIn, Facebook and Instagram.